The present invention relates to ink cartridges for ink jet printers for preventing the ink cartridges from being recharged with inks, and methods of making the ink cartridges.
Recently, thermal ink jet type printers have prevailed. The thermal ink jet type printer includes a print head which, in turn, includes a plurality of heating elements arranged in the form of an array on a substrate. The plurality of heating elements of the print head are selectively heated in accordance with printing information to heat an ink supplied onto the heating elements. Thus, a film boiling phenomenon in which bubbles are produced instantaneously on the interface between the ink and the heating elements is used to jet ink drops out of fine ink jet ports arranged in correspondence to the respective heating elements to thereby print information on recording paper. In order to compensate for the ink consumed in printing, an ink is appropriately supplied from an ink cartridge in which the ink is stored to the print head as requested.
Generally, there are two types of ink cartridges: one is of the type separate from the print head and the other is of the type integral with the print head. FIG. 1A is a schematic side view of an ink cartridge integral with the print head of an ink jet printer such as is mentioned above. FIG. 1B is a bottom view (or a head front view) of the cartridge of FIG. 1A. As shown in FIGS. 1A and lB, in this ink cartridge, the print head is unseparably integral with an ink tank 2 through an ink feeding section 3. The print head 1 is for color printing. To this end, the ink tank 2 has three ink chambers 4 (4a, 4b, 4c) in which three subtractive primary colors; that is, magenta, cyan, and yellow inks are filled.
The print head 1 has on its front substrate 5 three lines of nozzles 6 (6a, 6b, 6c) which respectively jet ink drops of the three subtractive primary colors. Such print head is generally made, using a silicon LSI technique and a thin film technique. More specifically, a plurality of heating elements (not shown) are provided in the form of an array on the silicon tip substrate 5. A partition which forms ink paths is disposed on the substrate, and further, an orifice plate is then layered to form the lines of nozzles 6, which jet inks, at positions on the orifice plate corresponding to the heating elements. The nozzles are supplied with inks through the ink feeding section 3 from the respective ink chambers 4 of the ink tank 2 corresponding to the lines of nozzles 6.
FIG. 2 is a decomposed perspective view of the ink cartridge 2. An ink tank itself 2a has an inside which is partitioned into three ink chambers 4a, 4b, 4c of substantially the same size arranged side by side with at least two surfaces of the ink chambers sharing an outer wall of the ink tank 2a itself.
The ink feeding section 3 positioned below the ink chambers 4 has three ink feeding holes 7 provided in correspondence to the respective ink chambers 4. The ink within the ink chambers 4a, 4b, and 4c are fed through the ink feeding holes 7 to the lines of nozzles 6 (FIG. 1B) in the print head 1 through ink paths (not shown).
Ink absorbents (not shown) are provided within the ink chambers 4a, 4b and 4c so as to prevent the inks from flowing uselessly to the outside due to gravity. An inner lid 2b is fixed to the top of the ink chambers 4a, 4b and 4c , for example, by thermal fusing or bonding. Three conductive holes 8 are formed in the lid 2b at positions corresponding to the respective ink chambers 4a, 4b and 4c such that inks are injected or filled into the ink absorbents within the corresponding ink chambers through the respective conductive holes 8.
After the inks are filled, a box-like space former 2c is thermally fused or bonded to the top of the lid 2b. The space former 2c has a small vent 11a on its top to form an air chamber 9 between the space former 2c and the lid 2b. The respective ink chambers 4a, 4b and 4c communicate with the air through air paths extending from the air vent 11a through the air chamber 9 to the respective holes 8. By this air ventilation, the ink chambers 4a, 4b and 4c are released from their sealed state such that the inks stored within the ink chambers 4a, 4b and 4c smoothly flow out to the print head 1.
When the inks are consumed and no sufficient quantities of inks remain in the ink chambers of the ink cartridge, the ink cartridge is removed along with the print head from the printer since the cartridge is integral with the print head, and a new ink cartridge integral with a new print head is instead set in the printer for use. If the cartridge is not integral with the print head, only the ink cartridge is removed and replaced with a new one. Anyway, the cartridge has a structure in which recharging the ink cartridge with inks is not considered.
Some users of the printer may try to recharge with inks its ink cartridge whose ink recharging is not ordinarily considered. To this end, the user drills a hole in position in a surface of each chambers 4a, 4b and 4c common to an outer surface of the cartridge 2a to achieve fluid communication between that ink chamber and the outside, recharges a different ink of the same color as the ink stored in that chamber, from the outside through the hole into the chamber, and seals the hole with sealing paper, a film having an adhesive thereon or an elastic material such as rubber.
The ink recharged into the chamber will mix with the previous ink remaining in the ink absorbent. The recharged ink may have been made in a manner different from that in which the remaining ink was made and hence may be different in quality from the latter ink. If the recharged ink is of a low quality, the mixed ink may have a low quality. Especially, in the full color printing which reproduces colors of an original image by superposing fine colors, no satisfactory image would be printed often.
In addition, when an deterioration in the ink quality influences not only the ink hue, but also its composition, the nozzles could be sealed to thereby cause the printer to malfunction. In addition, when a low quality ink is used for recharging, it might seal the nozzles themselves before the resulting ink has a deteriorated quality due to mixture of the low quality ink and the previous remaining ink. If the recharged ink quality is ill-suited to the ink absorbent, the ink can leak and/or insufficient supply of the ink would occur. When the recharging hole is provided in the cartridge, the strength of the cartridge itself would decrease and the ink might leak due to insufficient sealing of the hole.
It is an object of the present invention to provide an ink cartridge into which no ink can be substantially recharged.
The above object is achieved by an ink cartridge which stores an ink fed to a print head which jets the ink depending on printing data, comprising:
a housing having an ink feeding section for feeding to the print head the ink stored in the ink cartridge;
at least one inner chamber included in the housing, fluid communicating with the air, and filled with an ink; and
an outer chamber provided between the at least one inner chamber and the housing, excluding the ink feeding section.
According to the ink cartridge, even when a recharging hole is formed in the inner chamber, the hole cannot be sealed. Thus, when the ink recharged into the inner chamber would leak to the outer chamber or when the outer chambers are being filled with other color inks, those different color inks would mix, such that satisfactory printing cannot be performed, using such cartridge.
In the ink cartridge, preferably, the outer chamber fluid communicates with the air and filled with an ink whose color is different from that of the ink stored in the inner chamber.
The outer chamber may be partitioned into a plurality of subchambers, one of which is an air chamber which places the inner chamber and the air in fluid communicating relationship. Preferably, the ink cartridge is integral with the print head.
According to the present invention, the above object is achieved by a second ink cartridge which stores an ink to be fed to a print head which jets the ink depending on printing data, comprising:
an ink storage chamber having an ink feeding section for feeding the stored ink to the print head; and
anti-sealing means, provided on at least a part of an outer surface of the ink storage chamber excluding the ink feeding section, for preventing a possible hole provided in the outer surface of the ink storage chamber from being sealed.
In the second ink cartridge of the present invention, it is difficult to form an appropriate recharging hole in the wall of the ink tank, and it is also very difficult to seal the hole completely. Thus, even when an ink is recharged, the ink would leak out from the hole to thereby soil the inside of the printer undesirably. Thus, recharging of an ink into the ink cartridge by the user can be substantially prevented.
In the second ink cartridge, the anti-sealing means is preferably provided on substantially the entire outer surface of the ink storage chamber excluding the ink feeding section. The anti-sealing means comprises a plurality of spaced convexities whose height is not less than 0.1 mm, preferably 1 mm, and the interval between any adjacent convexities is not more than 10 mm, preferably 5 mm. Preferably, the plurality of convexities each take the form of a ridge or a dot-like protrusion.
The anti-sealing means may comprise an outer wall provided through a space over an outer surface of the ink storage chamber, excluding the ink feeding section.
the ink storage chamber may comprise therein an inner chamber and an outer chamber surrounding the inner chamber. The ink cartridge is preferably integral with the print head.
Another object of the present invention is to provide an ink cartridge making method which can substantially prevent recharging of an ink even when no special anti-sealing means, as mentioned above, is provided.
The above object is achieved by a method of making a plurality of ink cartridges for use in an ink jet printer which has a print head which, in turn, has a plurality of lines of nozzles which discharges inks depending on data to thereby record the data, comprising the steps of:
making, using a single sort of mold or a plurality of sorts of molds, a plurality of sorts of ink cartridges which each include at least a plurality of ink feeding ports which fluid communicate through a plurality of ink paths with the plurality of lines of nozzles, and a plurality of ink chambers which fluid communicate with the plurality of lines of nozzles via the plurality of ink feeding ports, wherein the plurality of sorts of ink cartridges have the same appearance, and different arrangements of the plurality of ink chambers or different combinations of the plurality of lines of nozzles and the ink chambers which are placed in fluid communicating relationship through the plurality of ink feeding ports;
selecting inks of respective colors such that the respective colors of the selected inks fed to the plurality of lines of nozzles are fixed; and
filling the respective ink chambers of each of the plurality of
cartridges with the corresponding selected inks.
According to the cartridge making method, a plurality of sorts of ink cartridges are made having inner ink chambers of different compositions but having the same appearance which anybody can not discriminate one from the other. Thus, even when the user tries to recharge an ink into this ink cartridge, he or she cannot recognize from the appearance of the cartridge where in the cartridge what colors of inks are filled. Thus, the user cannot recharge required inks into the cartridge. Thus, only by shipping ink cartridges of different sorts as parts randomly without providing any special anti-sealing means in the cartridges, recharging of inks into the ink cartridge by the user can be substantially prevented.
In this ink cartridge making method, each the ink cartridge preferably is integral with the print head. Preferably, the plurality of ink chambers of each of the ink cartridges are arranged so as to cross all the plurality of lines of nozzles of the print head, and that the plurality of sorts of ink cartridges have different combinations of plurality of lines of nozzles and ink chambers which are placed in fluid communicating relationship through the respective ink feeding ports.
In the cartridge making method, each of the ink cartridge may have a fluid interface member integral therewith having a plurality of ink paths which place the plurality of lines of nozzles and the corresponding plurality of ink feeding ports in fluid communicating relationship. According to this method, the print heads can be made so as to have the same structure, such that they can be made easily to thereby reduce the manufacturing cost.